Effects of meteorological factors on the onset of Bell's palsy

Objective: The etiology of Bell's palsy (BP) has not yet been clarified, although viral infection or reactivation is probably a major cause. The objective of this study was to evaluate the effects of meteorological factors on the onset and incidence of BP. Methods: Meteorological data from 2007 to 2011 were obtained from the Web-based 'Monthly Weather Reports of the Meteorological Administration' database. Patients with BP who attended Incheon St Mary's Hospital during the same period, presenting on the precise day that their symptoms appeared, were included in this retrospective chart review. Twelve meteorological factors were compared for days on which BP onset was and was not observed. The weather conditions occurring 1-7days before BP onset (D_-1-D_-7) were included to assess any possible delayed effects of meteorological factors on the onset of BP. The seasonal and monthly distributions of BP were evaluated. Results and conclusion: The mean values for the meteorological parameters did not differ significantly between the days when BP onset did and did not occur. However, the maximum wind speed on day -1 (D_-1) was significantly higher for BP onset days than for days with no BP onset. The seasonal and monthly distributions of BP did not differ significantly. It is suggested that stronger wind speed of preceding day may be related to the occurrence of BP.